Birmingham International Airport yesterday dismissed a report which claimed dangerous levels of toxic gases had been detected at the airport as misleading.

The study by the Chartered Society of Physiotherapy claimed BIA, along with Heathrow, Gatwick and Newcastle, exceeded recommended levels of nitrogen dioxide fumes by as much as 75 per cent.

The report said NO2 readings at Manchester, Liverpool, Blackpool, Sheffield, Humberside, London City, Southampton, Exeter and Gloucester Airports were up to 50 per cent higher than the EU target.

But John Morris, head of corporate and community affairs at BIA, said the CSP had chosen to use data gathered by the side of the M42 for its survey rather than results from the airport's own on-site monitoring station, which were independently verified.

More than 90 per cent of the traffic on the M42 had no connection to the airport, so using the results was "bizarre", he said.

He added: "I'm no scientist, yet even I can see that to rely on an off-site survey when better data are available, is likely to produce erroneous and inaccurate results.

"Using a survey station plonked on top of the M42, when we have independently-verified station on site, is going to give misleading results so far as the airport activity is concerned.

"I would imagine that other airports are also incensed - the report puts Exeter, with 671,000 passengers a year, in the same league as Manchester, with 20 million passengers a year. Clearly something is a bit iffy about their report."

Mr Morris said the airport had had an on-site monitoring station since 1995, which was overseen by both Solihull and Birmingham councils, and it had never recorded any excessive levels of NO2. ..SUPL: